<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Having A Ball by SoloShikigami</title>
<style type="text/css">

body { background-color: #ffffff; }
.CI {
text-align:center;
margin-top:0px;
margin-bottom:0px;
padding:0px;
}
.center   {text-align: center;}
.cover    {text-align: center;}
.full     {width: 100%; }
.quarter  {width: 25%; }
.smcap    {font-variant: small-caps;}
.u        {text-decoration: underline;}
.bold     {font-weight: bold;}
</style>
</head>
<body>
<h1><a href="https://archiveofourown.org/works/25638493">Having A Ball</a> by <a class='authorlink' href='https://archiveofourown.org/users/SoloShikigami/pseuds/SoloShikigami'>SoloShikigami</a></h1>

<table class="full">

<tr><td><b>Category:</b></td><td>Undertale (Video Game)</td></tr>

<tr><td><b>Genre:</b></td><td>Alternate Universe, First Time, M/M, Mating Cycles/In Heat, Nightmare Sans - Freeform, Pink Nightmare Sans, Tentacles</td></tr>

<tr><td><b>Language:</b></td><td>English</td></tr>

<tr><td><b>Status:</b></td><td>Completed</td></tr>

<tr><td><b>Published:</b></td><td>2020-08-01</td></tr>

<tr><td><b>Updated:</b></td><td>2020-08-01</td></tr>

<tr><td><b>Packaged:</b></td><td>2021-05-05 11:15:46</td></tr>

<tr><td><b>Rating:</b></td><td>Mature</td></tr>

<tr><td><b>Warnings:</b></td><td>No Archive Warnings Apply</td></tr>

<tr><td><b>Chapters:</b></td><td>1</td></tr>

<tr><td><b>Words:</b></td><td>3,201</td></tr>

<tr><td><b>Publisher:</b></td><td>archiveofourown.org</td></tr>

<tr><td><b>Story URL:</b></td><td>https://archiveofourown.org/works/25638493</td></tr>

<tr><td><b>Author URL:</b></td><td>https://archiveofourown.org/users/SoloShikigami/pseuds/SoloShikigami</td></tr>

<tr><td><b>Summary:</b></td><td><div class="userstuff">
              <p>Nightmare hates monster biology, so he goes on a search for a way to deal with his heat when he comes across a pink version of himself. Strawberry is only too happy to help him with his little problem, but Nightmare is going to make him fight for his right first.</p>
            </div></td></tr>

<tr><td><b>Relationships:</b></td><td>Sans/Sans (Undertale)</td></tr>

<tr><td><b>Comments:</b></td><td>9</td></tr>

<tr><td><b>Kudos:</b></td><td>247</td></tr>

</table>

<a name="section0001"><h2>Having A Ball</h2></a>
<div class="story"><div class="fff_chapter_notes fff_head_notes"><b>Author's Note:</b><blockquote class="userstuff">
      <p>Fic for my friend Rittoh! &lt;3</p>
    </blockquote></div><div class="userstuff module">
    
    <p>               Nightmare half-stomped, half-slithered down the corridor that served as a cross-path between universes. It was usually empty, as most monsters who had access to it usually just passed through quickly, and those who lingered were either ignorant of what it actually was, were looking for trouble, or looking for… something else.</p><p>               The goopy monster would never admit out loud that he was there for a purpose under the “something else” category. His tentacles waved restlessly, his body dripped more than usual, and anyone standing within three feet of him would have been able to feel the heat rolling off his body.</p><p>               Nightmare hated monster biology.</p><p>               “Mmmm, honey, do you believe in love at first sight, or would you mind slithering by me again?”</p><p>               Nightmare spun to the voice and saw what looked like a pink version of himself, tentacles, goop, and all.</p><p>               “You certainly look like the type of monster who knows how to show someone a good time,” they flirted. They looked him up and down with a slight smirk. “Or perhaps you need someone to show <em>you</em> a good time.”</p><p>               “Mind your place,” Nightmare snarled at them. “If you have no business in this area, then I suggest you leave, or I will <em>make</em> you leave.”</p><p>               “Is that so?” the other said in an easy, friendly tone. “I’d hate to see you go, but I bet I’ll love watching you leave.”</p><p>               Nightmare’s face blanked; was this monster flirting with him?</p><p>               “Just who the hell do you think you are?” Nightmare growled dangerously.</p><p>               “Ah! Yes, an introduction is in order,” the other said with a smile, walking up briskly to Nightmare. “I know they call you Nightmare; they call me Strawberry, and I assume that we’re cut from the same cloth.”</p><p>               As Strawberry got close, the ends of Nightmare’s tentacles turning to sharp points and he had them at the ready.</p><p>               “As such, perhaps I am the one who can stoke that fire you got burning,” Strawberry purred, leaning in towards Nightmare despite the sharpened tentacles coming threateningly close.</p><p>               <em>Is he serious?!</em> Nightmare thought, leaning back from Strawberry as the other looked as if he were going to kiss him.</p><p>               But instinct was winning out in Nightmare’s decisions, and that instinct was telling him that there was no way in <em>hell</em> that he was going to let this pink pile of goop get the best of him!</p><p>               So he leaned in and hissed in the face of his offender, baring his needle-sharp teeth and his tentacles closing in even more threateningly. If the other monster knew what was good for him, he would high-tail it as far away from Nightmare as he could.</p><p>               “You’re so cute!”</p><p>               Nightmare froze; that was literally the last reaction he expected.</p><p>               <em>What the hell?</em> Nightmare thought. <em>Is this guy for real?</em></p><p>               Apparently he was for real, as he was still staring at Nightmare with twinkling eyes and his fingers on his cheeks.</p><p>               “Really! You’re incredibly cute! Trying to look all threatening, meanwhile you’re so far into heat that you’d fuck just about anything that moves, wouldn’t you?” Strawberry said brightly, his tone similar to one who was talking to a child rather than the Lord of Nightmares and Darkness.</p><p>               “So you’ve chosen death,” Nightmare murmured.</p><p>               “Hm?” Strawberry replied, tilting his head to one side.</p><p>               Nightmare went to attack, but he felt his tentacle being restrained. He glanced around to find pink tentacles had coiled around his black ones, and the small giggle from his doppelganger drew his attention.</p><p>               “Now, now, we can either do this the easy way, or we could do this the fun way.”</p><p>               Strawberry smirked at him, and with a snarl, Nightmare struggled in his grip, coiling his own tentacles back around the pink ones and lunging forward. Strawberry went with it, though using his own to curve around them to keep from rolling onto the actual ground as their wrestling match began.</p><p>               Nightmare lashed out with claws and snapped at the other monster with his teeth. Strawberry easily dodged all of the attacks, giggling, making coos and croons all throughout.</p><p>               “Ah, almost! You’re so cute when you snarl like that. Nice try, there! Aww, baby bit down too hard on nothing? Careful, cutie, you might chip a fang. Come on, you can do better than that, can’t you?”</p><p>               Strawberry was a horrid tease and it was driving Nightmare crazy.</p><p>               “Would you just stay still?!” he growled out in frustration.</p><p>               “Well where’ the fun in that?” Strawberry said, slightly breathless as their hands were locked and pushing against each other in a fight for domination. “I don’t know about you, but I like it when my partner struggles a little. Makes it more interesting.”</p><p>               Nightmare growled, then he eased up his grip and relaxed his arms, making Strawberry fall forward and Nightmare rolled and ended up with getting Strawberry into a chokehold.</p><p>               “I don’t know if I want to kill you or fuck you,” Nightmare murmured into the side of the other’s skull.</p><p>               “Both sound interesting,” Strawberry said, wriggling in Nightmare’s grip. “But I’m willing to bet that I will be just what you’ll need to work that nasty heat kink out of you.”</p><p>               “Being in heat is not a kink!”</p><p>               The small distraction was all Strawberry needed to free himself from Nightmare’s hold and their wrestle began anew. Their black and pink tentacles had interlocked together and created a protective ball around them; Strawberry thought it was quite convenient, as it protected them from being injured, protected them from running into anyone and hurting them, and it gave them privacy. Strawberry wasn’t opposed to having spectators, but he figured Nightmare would heavily object to them.</p><p>               “Feeling like I treaded on a nerve, there,” Strawberry said. “Why don’t you just be a good boy and submit to me, then? I promise to make you feel really, really good.”</p><p>               “Never!”</p><p>               Strawberry giggled.</p><p>               “Well, then, you better make this interesting, at the very least, cutie pie.”</p><p>               Nightmare snarled and the wrestling began anew, the two rolling, trying to overpower one another, Nightmare worked to curl his tentacles around Strawberry’s neck or any of his limbs, but he simply countered them. It seemed for a while that their struggle would end in a stalemate when Strawberry started using what Nightmare would have considered dirty tactics.</p><p>               Nightmare faltered when he felt a tentacle brush up between his legs.</p><p>               “Stop that!” he demanded.</p><p>               “Why? Isn’t that part of the game?” Strawberry asked, sliding a tentacle around Nightmare’s waist. He almost had control, but Nightmare slipped out of the hold.</p><p>               Nightmare then grabbed Strawberry by the wrists and shoved him against the side of the ball, but another tentacle slithered over his ass, slipping between the cheeks which gave Strawberry enough leeway to break free when Nightmare was distracted.</p><p>               “Ah, you like pinning people down, hm?” he asked in a flirtatious voice. “You know, I have a bit of a theory about that; unless you’ve had a conversation with your love partner about what they do and don’t like in the bedroom, you’ll tend to do things to them that you wish for yourself.”</p><p>               As Strawberry spoke, he was moving in a way that he could draw Nightmare into a bit of a trap, and as his heat was beginning to play with his mind, it was a little easier than he thought.</p><p>               “That makes no sense,” Nightmare growled, his movements becoming unfocused in some ways and sluggish in others. “Why would I submit to the likes of you?”</p><p>               Strawberry giggled, and then pulled away from Nightmare, who smirked as he believed the other was retreating, but then he felt something wrap around his limbs suddenly and tighten the moment he tried to move forward. With a shout and snarl of anger, he fought against the bond. His legs were spread and pinned, his wrists gathered and held above his head, leaving him exposed and helpless.</p><p>               “Hee hee, I believe that I win,” Strawberry said.</p><p>               “You cheating bastard!” Nightmare growled, still fighting against the tentacles that bound him.</p><p>               “Now, now, don’t be a sore loser,” Strawberry said, leaning against one of his own tentacles as if it were a wall. “To the victor goes the spoils, as they say, however, I much prefer my bedmates to be at least somewhat willing.”</p><p>               Strawberry looked Nightmare up and down; the poor monster looked uncomfortable, and while anger was burning in his eyes, an unmistakable flush was on his cheeks, and desire and want was making slight whimpers escape from his throat. His heat was going to betray him any moment.</p><p>               “I can simply wait until your heat makes you submit,” Strawberry pointed out. “I don’t know how much longer you think you can hold out, but whatever you’re thinking, it’s a lot less than you believe.”</p><p>               Nightmare wriggled and growled, making it very clear that he was not happy with his current position. But if he took a moment or two to be honest with himself, he knew that Strawberry was right and he was going to have to succumb to his heat sooner or later, and it was preferable to have a partner than take care of it all on his own.</p><p>               “Fine,” he snapped.</p><p>               “Only if you’re sure,” Strawberry said with a gentle smile. “I don’t want to be a cause for regret or anything.”</p><p>               “You won, so... it’s fine,” Nightmare muttered, his face flushing as he realized he was naturally settling into submission.</p><p>               “Really?” Strawberry asked, excitement in his voice and sparkling in his eyes.</p><p>               “Yeah.”</p><p>               Strawberry let out a squeal of joy, tackling Nightmare in a hug and rubbing against his face.</p><p>               “May I kiss you?” he purred.</p><p>               Nightmare sighed and gave a slight nod. Strawberry smiled and leaned in, nuzzling his mouth before kissing him gently. Nightmare sighed and relaxed a little, having to admit to himself that it felt really nice. Strawberry took it a little further after a moment, carefully licking at Nightmare’s mouth in invitation. Nightmare would have made an exasperated sigh, but inside he slowly opened his mouth and let his tongue tentatively touch Strawberry’s.</p><p>               The other surged forward with a happy hum, invading Nightmare’s mouth, exploring, seeking out sensitive spots, and distracting him from the wandering fingers that began to move over the rest of his body.</p><p>               Though the magic goop that covered their bodies hid a lot, Strawberry had no problem finding the edge of Nightmare’s shirt and he slipped his hand underneath it. Strawberry brushed down Nightmare’s sternum and across his lower ribs, then he began to lightly stroke his spine. Nightmare squirmed under the touch, wanting to get away from it while also wanting to press into Strawberry’s wandering hands.</p><p>               “You’re are so adorably handsome,” Strawberry murmured.</p><p>               “Am n-not,” Nightmare muttered.</p><p>               “Oh, you are, you really are,” Strawberry said, rubbing their cheeks together. “And the more you resist it, the more attractive you become.”</p><p>               He captured Nightmare’s mouth in another searing kiss before he could protest again. Nightmare whimpered, wanting attention elsewhere as his body demanded his heat to be satisfied. Strawberry’s hands began wandering lower, finding the waistband of his shorts and carefully pushing them down.</p><p>               Since they didn’t snag on anything, Strawberry didn’t have to guess how he was going to proceed. Nightmare could feel the pink demon smirk against his mouth as his fingers began to move closer to the soft mound forming between his legs.</p><p>               “That’s a good boy,” Strawberry murmured as his fingers began brushing through the folds of magic. “Just relax and let sweet Strawberry take good care of you.”</p><p>               Nightmare growled, but the threatening sound ended in a whimper as Strawberry’s fingers continued exploring his forming magic. Nightmare’s pussy also formed some small tendrils, and they kept slithering around Strawberry’s fingers as they teased and touched.</p><p>               “Heh, heh, if you’re not going to tell me what you like, your body seems eager to clue me in,” Strawberry said with a chuckle. “See how they try to grip onto me when I’m going cross a spot you like?”</p><p>               Nightmare tensed a little, but he still tried to move into Strawberry’s touch as his tendrils gripped his fingers in an effort to focus his attention.</p><p>               “Yeah, and I guess this spot does nothing for you, since they slither around as if trying to guide me elsewhere. That’s interesting.”</p><p>               Strawberry continued to touch and explore, meanwhile Nightmare was trying and failing to keep himself together.</p><p>               “Please, Strawberry, don’t tease me anymore,” Nightmare begged, still trying to arch into his hand.</p><p>               “Aww, sweet Nighty, I can’t say no to you when you beg like that,” Strawberry crooned, leaning in to kiss him again as he pushed down his own shorts.</p><p>               Nightmare growled and tried to twist, indignant of the way he was being treated and spoken to, but he was still helplessly bound and more wanting of the contact that would satisfy the insufferable burning in his body.</p><p>               “Shh, it’s okay, Nighty, I’m going to make you feel real good,” Strawberry murmured, pressing his body against Nightmare, grinding his cock against him.</p><p>               Nightmare went still, partially because he wanted nothing more than to be given what he wanted, but there was a slight panic as he realized how big Strawberry was.</p><p>               “Mmm, I can feel how wet you are,” Strawberry murmured, rubbing himself against Nightmare, his cock sliding through his magic, using the wetness dripping from him to lube himself up a bit. “I’m gonna make you mine.”</p><p>               Nightmare whimpered again, and when Strawberry began to penetrate him, he finally stilled, letting out a slight wince.</p><p>               “Shh, shh, it’s okay,” Strawberry murmured, putting one hand on Nightmare’s hip to keep him steady and using the other to caress his cheek. “Just a bit more, you’re doing so well.”</p><p>               Nightmare wriggled and whimpered, trying to roll his hips up to get more of Strawberry inside, but then letting out small cries as the other’s thick cock stretched him.</p><p>               “Mmm, there we go, snug,” Strawberry said with a satisfied sigh when he was almost completely seated inside of Nightmare. “You’re so tight, it’s delightful.”</p><p>               Nightmare’s face was completely flushed and he was looking wrecked already, but he had gone oddly silent and still. Strawberry looked down at him, analyzing.</p><p>               “Hey… is this your first time having someone in you?” he asked.</p><p>               Nightmare gave a small start, his face flushed even more.</p><p>               “It is!” Strawberry gasped, a blush forming on his own face. “Oh, my, no wonder you’re… are you okay? I’m not hurting you, am I?”</p><p>               “N-no,” Nightmare muttered, looking away. “B-but, please, I, uhm…”</p><p>               Strawberry tilted his head to the side, then in an experimental sort of fashion, he thrust in a bit more. Nightmare made a choked sound, but still tried to move into it.</p><p>               “Aww, so cute,” Strawberry said, leaning down to rain gentle kisses all over Nightmare’s face. “Don’t worry, my darling, I got you.”</p><p>               Strawberry went slowly, pulling out ever so slightly before pressing in again, this time making sure he slid in all the way. He pulled out again, just a bit, before thrusting in a little harder. Then he pulled about halfway out before slamming into Nightmare and finally wringing a cry from him.</p><p>               “Good boy,” Strawberry said, leaning down to lick his neck before beginning to hump into him again at a slow and steady pace. “You know what this means, don’t you? I’m your first, now you belong to me.”</p><p>               Nightmare’s head was spinning from his heat and from the sensations of being fucked, therefore he couldn’t articulate a reply.</p><p>               “I’ll be the only one who can make you feel this way, the only one who can fuck you the way you like, I’m going to make sure your body can only accept me,” Strawberry swore as he started to move faster.</p><p>               “Y-you’re crazy,” Nightmare panted, finally able to form words.</p><p>               “But this feels good, doesn’t it?”</p><p>               Strawberry was smirking down at him knowingly, Nightmare growled, but it was cut short as he moaned when Strawberry moved a tentacle under Nightmare to lift his hips up more, changing the angle of his thrusts.</p><p>               “Come on, Nightmare, let me hear you say how much you love being fucked by me,” Strawberry purred.</p><p>               The pink monster slowed his thrusts, pausing when he was hilted and rolling his hips for a bit before pulling out again slowly. Nightmare grimaced and thrashed, trying to break free of the tentacles binding him. He stilled when Strawberry slipped his hands under his shirt again and stroked at his ribs as he bent in close to kiss Nightmare.</p><p>               “It’s not that bad, now, is it?” Strawberry asked, now switching to short, shallow thrusts. “I’m making you feel good, I’m treating you well, even making sure our affair is private and no one can see us; it wouldn’t be so terrible to belong to me, would it?”</p><p>               Nightmare began trembling, his orgasm approaching, spurned on by Strawberry’s thrusting and his words.</p><p>               “P-p-please,” Nightmare whimpered after a minute. “Strawberry, please, make me cum?”</p><p>               “Oh, ho, ho, begging, hmm? That’s really hot,” Strawberry purred. “You want to cum, baby?”</p><p>               Nightmare groaned, then whimpered as Strawberry thrust in hard.</p><p>               “Come on, sweetie, tell me again what you want,” Strawberry encouraged.</p><p>               “Mmph, please, m-make me cum,” Nightmare begged again.</p><p>               “Only because you asked so nicely, cutie pie,” Strawberry said, nuzzling Nightmare’s face before pulling back and gripping onto his hips.</p><p>               It didn’t take much more before Nightmare was shaking and whimpering.  Strawberry rubbed his clit, the tendrils gripping his fingers hard, and finally he shouted as he came.</p><p>               “Ohh, Nighty, it feels so good to feel your pussy tighten around me. Hang in there for another minute, I’m almost there.”</p><p>               Nightmare trembled and moaned, and nearly came again as Strawberry quickened his pace, panting and moaning before he also came, thrusting into Nightmare deep and hard, filling him with his pink magic.</p><p>               He leaned over Nightmare, kissing him gently, murmuring praises against the other’s mouth. Nightmare was still shaking as they both came down, dazed, but satisfied.</p><p>               “Mmm, that was so good,” Strawberry murmured, letting Nightmare’s hands go and guiding them down to rest, pulling him in for a snuggle. “I don’t think you’re quite done yet, so take a nap, and when you wake up, I’ll be here to make love to you again.”</p><p>               Nightmare blinked blearily at Strawberry; he was so tired and drained, and while he was partially irritated with this pink doppelganger, the pink demon did make him feel better than he had felt for a while. He gave the other a nod and closed his eyes, shifting to make himself comfortable against Strawberry and he dozed off.</p><p>               “Don’t worry, Nighty,” Strawberry murmured, caressing his skull. “I’ll protect you, forever.”</p>
<hr/><p>
  <em>Meanwhile, outside…..</em>
</p><p>               Dust was shuffling through the cross-path corridor when he came across the goopy pink and black ball. He recognized the black goop as Nightmare, but the pink threw him off.</p><p>               “The heck is this thing?” he wondered. “Boss?”</p><p>               Dust poked at the ball, but suddenly the pink and black spikes thrust out from the ball’s surface, making Dust jump back.</p><p>               “Boss is in there still?” Killer asked, approaching Dust.</p><p>               “Yeah… I guess so.”</p>
  </div><div class="fff_chapter_notes fff_foot_notes"><b>Author's Note:</b><blockquote class="userstuff"><p>Like what you read? Please check out my social media for more fun!<br/><a href="https://soloshikigami.tumblr.com/"> My Tumblr</a><br/><a href="https://twitter.com/SoloShikigami"> My Twitter</a></p></blockquote></div></div>
</body>
</html>